Air conditioner



Sept 17,/1957 A. E. KLINE ETAL AIR CONDITIONER' -Fi1ed April 6. 1953 e Sheng-sheet 1 Sept 17, 1957 2,806,361

A. E. KLINE ET AL AIR CONDITIONER Filed April 6, 41953 6 Sheets-Sheet 2 A "I ll- .ir 37 @l M 47. |1272" Sept 17, 1957 A. E. KLINE ETAL AIR CONDITIONER 6 Sheets-Sheet 5 Filed April 6, 1953 i v INVENTORS .m Z//f s.

Sept 17, 1957 A. E. KLlNE ETAL 2,806,361

AIR CONDITIONER Filed April 6, 1953 6 Sheets-Sheet 4 O OOOQOOOG Sept 17, 1957 A. E. KLINE ET'AL 2,806,361

- AIR CONDITIONER' .Filed April 6, 1955 e sheets-sheet 5 IN V EN T ORS.

Sept 17, 1957 A. E. KLINE ErAL 2,805,361

AIR CONDITIONER Filed April 6, `1953 6 Sheets-Sheet 6 United States Patent O AIR CONDITIONER Arthur E. KlinevandvWendell H. Webster, Albion, Mich., assignors, by mesne assignments,` tojMcGr/aw-Edirson This invention relates to airconditioning apparatus and more` particularly to the typeof air conditioning apparatus designedto be mounted in awindowof a 'buildingand to'occupy minimum space within the room so as not to project beyond the window sill.

In the use of window type lair conditioners, it has been found necesary to arrange the parts comprising the units in compact form to carry and support the same as selfcontained portable structures in the openings of the win'- dows. Due to the requirement of'compactness, the arrangement of the parts was not as simpiy carried ont in design asmight be desired to secure niinimu'm' protrusion from the window sill. This protrusion of the air conditioner units has been a real objection although very little effort has been made to decrease the depth of the units to eliminate this objection. As a result, most structures protrude unduly beyond the window sill into the room and are not only unsightly dueV vto their "bulkines's, 'bu't"occupy valuable space within the room.

It is an object of the present invention to provide a new and improved air conditioning structure ofthe selfcontained window type th-at willoccupy minimum'space within the room and preferably project into the room a distance no greater than the depth of thewindow sill.`

It is a further object of the present invention to provide a -new and improved air conditioning structure of the self-contained window type that willnot only project into the room a distance no greater than the depth of the window sill, but a distance outwardly no greater than the normalv for a device of this type.

It is a further object of the inventionto provide a new and improved air conditioning structure of the yself-con,` tained window type that incorporates 4thereinirnproved forms of fan construction for yboth the evaporator and condenser units whereby the depth of the` air conditioning structure can be decreased toa point never obtainedfhere-y tofore for the same capacity of ,air conditioningfstnctiire,

Further objectsand advantages of theinventionvi/'illzbe clearly apparent from` the following detail., description when taken` in connection Iwithfthe I'accompanying drawings which form -a part'thereoff.

' In the drawings:

Figure 1 is a perspective view of a window openingvand air conditioning unit embodying the presentA invention, one side of the window frame being omitted and the board and attaching members Abeing shown in exploded position;

Fig, 2 is a transverse section of a window frame illustrating in dotted lines the approximate area occupied by an air conditioningu'nit einbedylinlgy the` IQSQQ V'CUQEQ evaporator unit;

it being understoodthat this occupied area, is in relation to therwindow shown 4and that itv may vary according to the construction ofthe Wi`ndow;`

Fig. 34is a top view with the housing removed of an air conditioning unit embodying the present invention; Fig.` 4 is a front viewof `the same withl the housing removed; Fig. 5is a side view also with the housing removed;

Fig. -6 is aV transverse section vtaken along line 64-6of Fig. 3'1ooking in the direction ofthe arrows and illus: trating the condenser fan and unit inelevation; Fig. 7 is a transversesection taken along line 7-7 of Fig. 3 looking in the direction of :the arrows and illus# trating in front elevation the fan of the Vevaporator` uniti Fig'. '8 i's a section taken along 'line 8'-81ofFig.` 3 `looking inthe direction of the arrows; f Fig. 9 is a detailelevational view of the damper door and its mounting controllingthe 'owfof air so as either to recirculate the air in the room, to' supplyfresh air from the outside, or to exhaust the air from the room;

Fig. 10 isa top view partlyinsection and illustrating the position of this damper door at thev time of providing either one of the aforesaid three positions; 'i

Fig. 11 is anelevational view of one face of the fan for the condenser unit; Fig. 'l2 Vis a top elevational view of the same taken along line 1 2-412 of Fig. 11` and looking in thedirection of the arrows; l

Fig. 13 is a sectional view taken along line 13-13 oi Fig. 1l and looking in the'drelction 'of the arrows;` Fig. 14"is` a fragrrtentaryffdetail view4 ofa portionot the condenser fan after the cutting operation but before the bending'operation of the blades thereof;

Fig."15 is a fr-nt'elevationalwiew' of the fan for the Fig. 16` is atop elevational View thereof:

Fig. 17 s a transverse section takenalong line 17,-.17,

of Fig. 15 and looking in the directionof the arrowsyand Y Fig. 18 is a similia-rV View 'but taken along line 18-18 of Fig. '15 and looking in the direction of the arrows.`

`As shown in the drawings, an airconditioning unit e'm` bodyingthe presentinvention comprises a baseflt)v adapted toV receivea housing 11 havingal Vfront coverA 12l detach-l able at` 13.' Cove'r 12is provided with; a 'grille'pan'el'-14 having openings 15 therein: through"whichy airv froml the room is drawnand', passed through a filter 16 which Vwill -be accessible'for'replacement' when hinged panel 17fis opened. Panelfl?,iscarriedby'front cover 12 andhas ther'i'na series of Yopenings .'IISthroigh which cooled'air is dischargedinto'ithe room,

l A vcontijil` panel 19havingn a series o f knobs 20, Z1l and'ZZ isconvenientlydisposedlat the front so thatvupon the opening ofy hinged panel 1:7., these kngobs will. be readily accessible for opera-tion. Knob 2Q operates a damper 23 controlling ythe now of air through an opening designated generally as '2.4 in Figs. 3v. andj 1.0. Damper 23V is so mounted that it., may be moved -t o one of three positions by knob 2,0.

' I t will no w be shown how manual rotationl of Control knob Ziletiects position-ing'of circulation controllingvalve ordarnper 2,3 impositions A., B` o r C. Note in Fig. 5 that knobK 2i):` is journaled for rotation ink panel 19 and ythat s aid'klnob carries a. beveled gear 10,0 on the side of the panel4 opposite the knob: Gearl lktlQAis meshed with anf other beveled gear 101 which is rightly carried on a crank shaft 102 extending downwardly and terminating in a free end 103 which passes loosely through a slot 104 in bracket 105 affixed to damper 23. Hence, it is evident from examining Figs. 5, 9 and 10 that rotation of crank shaft 102 through the agency of knob 20 will cause free end 103 of vthe crank shaft to reciprocate in slot 104 so that bracket 105 will swing in a horizontal plane and damper 23 will alternatively swing on its left main hinge 107 or its right main hinge 109 so as to assume positions C and B, respectively (see Fig. 10).

vThe damper assembly is of unusual construction in that it enables swinging door 23 through its lopening 24 in partition 99 from either edge thereof. In Figs. 9 and l() will be seen that there are really a pair of identical but opposite hinges, for example, lone includes a pair of main hinges 109 which are merely hooks extending through slots in partition 99 adjacent opening 24. A strap 109 extends across door 23 from main hinge 109 and termina-tes in an auxiliary hinge 110 which is in fact a hooked end formed on 109 to wrap around the edge of damper door 23. The second hinge is similar and it constitutes corresponding parts including a main hinge 107, a strap 107 and an auxiliary hinge 108.

If it is desired to opera-te damper 23 to position B for example, see Fig. 10, crank shaft 102 must be turned clockwise. This will cause free end 103 of the crank shaft to act on damper bracket 105 causing the latter to assume the dotted line position as shown in Fig. 10. Strap 109 will continue to lie against damper 23 but the damper will swing inwardly on hooked main hinge 109 and `on auxiliary hinge hook 108. Opposite main hinge 107 will remain substantially stationary during this event although damper door 23 will swing inwardly away from strap 107.

The same sequence of events .takes place when crank shaf-t 102 is turned counterclockwise when viewed from the top. Damper door 23 would, of course, swing to position C on main hinges 107. It may be noted that door 23 is provided with a pliable sealing sheet 112 bonded to the inner face thereof by any well known means; air leakage is thereby prevented for all of the three positions A, B and C. When damper 23 is in the position shown in full lines or position designated A in Fig. 10 and closing opening 24, air in the room is merely recirculated by passing it through the conditioner in the order of grille 14, evaporator unit 27 and out again through upper hinged panel 17 (see Figs. l and 3). When damper 23 is in the dotted line position indicated at C in Fig. l0, fresh air is drawn through a screencovered opening 26 in a portion of the side of housing 11 that projects beyond the window and outside of the room. This fresh air is then drawn through opening 24 and moved through lter 16 and over evaporator coils 37 disposed in the rear of filter 16, which coils 37 are a part of the evaporator unit designated broadly as 27. This air continues its movement by virtue of evaporated fan 23 into the chamber 28 of this evaporator fan and lthen upwardly through a passage 29 and moves forwardly through an opening 30 having a series of louvers 31 for directing the ow through openings 18 in outer hinged panel 17. Partition 32 houses evaporator fan 28 within this chamber 28 and the passage 29 and thuscontnes the currents of air by fan 28, which is of the centrifugal type and will be more fully explained later.

On the other hand, if damper 23 is in the dotted line position indicated at B in Fig. l0, air is exhausted from the room to the outside by reason of its movement through an opening 33 in a partition 34 extend-ing diagonally from the side wall of housing 11 which has the screen protected opening 26 exposed to the outside. With damper 23 in posit-ion B, fresh air from the outside cannot bedrawn through opening 26. However, a condenser fan 38, :to be more fully described later, draws airl through arcuate screen'2'6", opening 33, opening 24 and the room opening 15 in panel 14 in the front of housing 11. The air from the room is, therefore, partly moved through these openings and taken by condenser fan 38 through condenser coils 40 of the condenser unit designated broadly as 41. It will be understood, of course, that a portion of the room air is also circulated through filter 16 and over evaporator coils 37 by evaporator fan 28 which then circulates it forwardly through openings 30 and 15 and into the room in a cooled, filtered and dehumidied condition.

Both tie evaporator fan 28 and the condenser fan 38 are driven by a motor 43 disposed between the same and mounted upon a bracket 44 secured to a raised portion 45' in base 10. Motor shaft 45 carries these fans at opposite ends, the arrangement being that minimum space is occupied by the parts so that the evaporator uni-t 27 and the condenser unit 41 may be disposed as closely together as possible upon base 10 with the motor 43 spaced therebetween.

The refrigeration apparatus includes the usual hermetically sealer motor compressor 46 carried by spring mountings 47 extending upwardly from base 10. The refrigerant is circulated in a closed system by this latter unit through the evaporator unit 27 and the expanded gases are then passed through the condenser unit 41. It will be understood lthat the refrigeration apparatus is standard equipment and that it is not a part of the present invent-ion. The bottom or base 10 is formed to provide a well or depressed 4area 48 directly below the evaporator unit 27. This well 48 connects by a channel 49, see Fig. 3, with another well or depressed area 50 below the condenser unit 41. The condensate forming on evaporator coils 37 will drain into well 48 and will flow by way of channel 49 to well 50. The condenser unit 41 is disposed in an enclosure including top wall 51, side wall 52 and a partition 53, the latter having a central opening 54 into which condenser fan 38 projects (Fig. 8). Partition 53 extends down to the floor of well 50, but it is provided with an opening at 55 in one corner (Fig. 6) to permit the condensate to flow around this partition 53 into well 50. 1f the condensate is sufficient, it will risc to a level above the lower edge of a slinger ring carried by and rotatable with condenser fan 38.

Slinger ring 60 will pick up the condensate and throvl it against the condenser coil 40, effecting evaporation thereof. This evaporation increases the eciency of condenser coil 40 because this evaporation tends to lower the temperature which aids the cooling action and thc vapor is discharged therefrom to the outside. From the description thus far, it will be apparent that the parts of the air conditioning apparatus disclosed herein arc compactly arranged.

It will be observed, however, that the design of both fans directly becomes a part of the general arrangement effecting such compactness decreasing the depth of the apparatus that when the apparatus is lmounted in a window opening as illustrated in Figs. l and 2, the front face 61 of cover 12 is substantially flush with the edge of the sill 62 and there is no overhang or protrusion into the room as heretofore experienced. Without in any way decreasing the capacity of the apparatus, we have been able to reduce the depth, say, to twenty-two inches, which is considerably below the dimensional requirements structurally for devices heretofore of the same capacity.

Condenser fan 38, as shown in detail in Figs. ll to 14, is preferably formed from a single sheet of material. It is provided with a plurality of blades 65 `shaped so that their length is in the neighborhood of one-fourth of the diameter of the fan. With slinger ring 60 integrally formed about the fans periphery, each blade 65 is then formed by punching out holes 66 and 67 in the body 68 and by making an incision 69 between these holes and defining the outline or outer edge of the blade. Forming tools are then used to press the material between these holes' and 4within the incision outwardly into the shape of each blade, it being noted that certain of these forming tools engage at points 70 and 7l (Fig. 14) to press inwardly while the blade is pressed outwardly or, relatively speaking, in the opposite direction. The outer edge 72 of each blade (Fig. 11) then extends outwardly or away `from the fan body while the inner edge 73 extends outwardly slightly beyond the plane of the fan bodyvbut in the opposite direction. The material lying between a straight line extending from hole 66 to hole 67 and incision lineV 69 of the next blade becomes the axis of each blade as it is formed, and, as a novel consequence, the inner edge 73 moves beyond the plane of the fan body in a direction opposite to the blade itself and its outer edge 72. Hence, a portion of each blade 65 extends outwardly from the slingerring 60 on opposite sides, which, to a certain degree, tends to minimize the depth of condenser fan 38.

As shown in Figs. 3 and 8, the curved portions of blades 65 extend from slinger ring60 on the side opposite to condenser coil 40 and only slightly beyond the hub 76 and thus lying almost within the vertical lplane of this hub. The opposite edges 73 of blades 65 project only a small distance lfrom the slinger ring 60. The currents of air drawn by these blades 65 pass through the openings 77 between the blades and are produced by virtue of the blades being cut out of the fan body itself. lt will also be noted that the blades 65 are continuous in their positioning about the fan and that no dead material is left between the blades. This provides a maximum effective blade `surface for the space occupied by the blades without decreasing the capacity and eliminates the requirement o f large blades of the propeller type that heretofore needlessly occupied space and contributed to awkward design and the projection of the air conditioning units a considerable distance into the room from the window sill. Moreover, the slinger ring 60 is uniquely arranged in a simple manner as noted in Fig. 8 to pick up condensate in well 50 and to distribute it into the air stream by throwing the condensate against the slanting side wall 52 of partition 53 forming a part of the condenser fan shroud and also against the slanting distributing flange 52' extending across and above the fan, and thence upon condenser coils 40 for evaporation and the added cooling thereofwhich will result from such evaporation. Fig. 8 very clearly shows the compactness resulting from the narrow depth of condenser fan 38. Central web portion 73 is reinforced by ribs 79, the formation of this web portion providing a strong central structure carrying hub 76.

VEvaporator fan 28 carried upon the ysame fan shaft 45 is disposed just inside partition 32. It comprises a single vertical or back wall 80 and a plurality of blades 81 and 82 projecting laterally therefrom. Blades 81 have webs 83 extending radially inwardly to connect with a hub S4 while webs 85 of blades 82 stop short of the hub and do not connect thereto. The webs connect with their blades in a manner to produce a centrifugal type fof fan which will draw currents of air to it at the central portion and which then permit the blades to force the currents of air centrifugally from the periphery. It will be noted that the back wall 80, the blades 81 and; 82, their webs 83 and 85 and the hub 84 are molded as a single piece. The molding may be of any suitable material and it is mentionedfthata plastic such as high impact styrene, an acetate or methyl methacrylate may be used, although any plastic with suitable stability and high impact value may be substituted. The construction of this fanY 28 permits it to b e very'compactly disposed between the evaporator c oil unit and,back partition 32 and occupy minimum space without decreasing the capacity to circulate and cool the room air, or to exhaust air or add fresh air at the same time.

The air conditioning unit is shown mounted in a wiri dow opening in Figs. l and 2, and, as previously explained, the unit rests upon the sill 62 and may be carried so that the front face 61y is approximately Flush with the edge of the sill Without protrusion therebeyond into the room. Itl will also benoted that the rear portion designated broadly as extends outwardly of the room and the window opening the same distance as at the present time for the same capacity of unit. The usual side window shields 91, window shield brackets 9,2 and .top window seal gaskets 9,3 are employed to seal the unit in the window frame, the usual base mountings (not shown) also being employed to carry the 'unit in position.

Without further elaboration, the foregoing will so fully explain the character of our invention that othersmay, by applying current knowledge, readily adapt the same for use under varying conditions of service, without eliminating certain features, which may properly be said .to constitute the essential items of novelty involved, which items are intended to be defined and secured to us by the following claims.

We claim:

l. In a window type of air conditioner, a combination of parts effecting a compact unit projecting inwardly of a window substantially equal to the depth of a normal window sill and outwardly of the window of a depth not exceedingthe normal of a device of this type comprising an evaporator unit, a condenser unit and a refrigerant circulating system for the two units, a fan for each unit, and means to drive the fans, the fan of the evaporator unit being of a icentrifugal type with its blades projecting laterally Yfrom a single mounting wall carried byy a hub to secure a reduced depth for said evaporator fan, la chamber for said. evaporator fan including a partition wall adjacent the free ends of said centrifugal fan blades 'and having an aperture concentric with the axis ofsaid fan communicating with said evaporator unit, sai-d partition wall also having an outlet opening aligned with the outer periphery of said centrifugal fan blades for expelling air drawn through said aperture, a baie interposed between said evaporator unit andvsaid outlet open-ing the fain of said condenser unit having la 'series of propel-ler blades of a length substantially in the neighborhroiod'of one-fourth the diameter of the fan to secure a reduced depth for said condenser fan.

2. Iny an air conditioning unit, a housing having twlo compartments, each provided with inlet and outlet means to permit passage of air therethrough, a refrigeration system including an evaporator mounted in one of said compartments and a condenser mounted in the other compartrrient,l means including an evaporator fan adapte'd` to ycirculate air in heat exchange relationship with the` evaporator an'd to discharge such air into a room, means including a condenser flan adapted to circulate air in heat exchange relationship with the condenser and to `discharge such air outside the room, a third compartment in said housing disposed along one of the outside walls of said housing, said outside housing wall having anv opening therein to supply outside air to said third compartment, said third compartment having two additional openings therein, one ot said openings leading to said evaporator fan and the other opening leading to said condenser flan,` a three-position valve member, said valve member comprising a door, a pair of oppositely directed substantially U-shaped arms supporting said door, the free ends of said arms hingedly engaging opposite margins of the door and the closed ends of said -arrns being hinged respectively on opposite sides of the opening leading to said evaporator lian, and means to shift saidl valve member into any one of said three positions to close ofi either of said two additional openings or said outside opening either to recirculate the room air by said evaporator han without outside air mixed therewithor with outside air mixed therewith or to exhaust the room air to the outside by said condenser fan.

3. In.` an airconditioning unit, 'a housing having two compartments, each provided with inlet and outlet means to `permit passage of air therethrough, a refrigeration system including Aan evaporator mounted inY one of said 7 compartments and a condenser mounted in the other compartment, means including an evaporator fan adapted to circulate air in heat exchange relationship with the evaporator and to discharge such air into a room, means including a condenser fan adapted to circulate air in heat exchange relationship with the condenser and to discharge lsuch air outside the room, a third compartment in said housing, said third compartment being disposed along an outside wall of said housing with an opening therein to supply outside air to said third compartment, said third compartment having two additional openings therein, one of said openings leading to said evaporator fan and the other opening leading to said condenser f'an, a valve member located in said third compartment at the intersection of said three openings and a single means to operate said valve member into any one of tihree positions to close off any one of the three said openings either to recirculate the room air by said evaporator fau without outside air mixed therewith, ou' with outside air mixed therewith, or to exhaust the room air to the outside by said condenser fan.

4. in an air conditioning unit, a housing having two compartments, cach provided with inlet and outlet means to permit passage of air through a refrigeration system including an evaporator mounted in one of said compartments and a condenser mounted in the other compartment, means including a centrifugal evaporator fan located in alignment behind said. evaporator and adaptcd to circulate air in heat exchange relationship with the evaporator and to discharge such air into a room, means including a `condenser fan adapted to circulate air in heat exchange relationship with the condenser and to disoli-argc such air outside the room, said outlet means of said evaporator compartment including a grilled opening above said evaporator in the front of said housing, a

chamber at the rear of said grilled opening, and a baffle separating said evaporator compartment from said chamber, whereby warm .fair llows in one direction into said evaporator coil beneath said baille and in an opposite direction out of lsaid outlet ychamber above said bathe.

5. An air conditioning unit comprising a housing, a condenser compartment having outlet means and inlet means leading to the interior of said housing, an evaporator fan :compartment spaced from and parallel with said condenser compartment, said evaporator flan compartment being open at the top and imperforate to air flow into said housing interior, a propeller fan extending into said condenser inlet means and a centrifugal fan in said evaporator fan compartment, a motor disposed within said housing interior and carrying each of said fans on opposed ends of its shaft in immediate adjacence to said motor, an evaporator compartment having an outlet aperture communicating with said centrifugal fan and an inlet opening, a chamber connected with said evaporator compartment through said inlet opening, said ychamber being substantially coextensive with the height of said evaporator compartment and having a top closure defini-ng the bottom of the passageway for the discharge from said centrifugal fan, a partition within said housing having an outside air inlet opening, an opening to said chamber and an opening t-o said housing interior, damper valve means ldisposed at the inter-section of the pathways leading to `said last three named openings, single control means for actuating said damper means to close one of said three openings, whereby closing said opening to said chamber places the outside air opening in communication with the interior ot said housing, and closing said interior opening admits outside air to said chamber and whereby closing said outside opening Icauses said condenser fan to exhaust room air through said chamber opening and said housing interior.

6. In an air conditioner of the type having a compartment with a heat adsorbing element therein, a compartmentV with a heat dissipating element therein, an air inlet and outlet to and from each' compartment, air circulating means for circulating air from an enclosure to be cooled and ambient air from outside the enclosure through the compartments having a heat absorbing and heat dissipating element, respectively, the combination with such an air conditioner of selective means for independently exhausting stale air from or adding outside ambient air to the enclosure comprising an open passageway communicating with the enclosure and the outside ambient, said passageway having ports communicating with the separate compartments at the suction side of the air circulating means, and a single movable damper mounted in the passageway to either close the port from the passageway to the compartment having the heat dissipating element and open the passageway or open said port and close the passageway between said port and the outside ambient.

7. An air conditioner in accordance with claim 6 in which the single movable damper is mounted in the passageway to close the port from the passageway to the compartment having the heat dissipating element or close the passageway on either side of said port.

8. An air conditioner in accordance with claim 6 in which the single movable damper is mounted to close the passageway between ports in one position, close the port from the passageway to the compartment having the heat dissipating element in another position to cause outside air to flow in one direction through the passageway to the suction side of the compartment having the heat adsorbing element, or close the passageway between said port to the compartment having the heat dissipating element and the outside ambient in another position to cause air from the enclosure to flow in the opposite direction through the passageway and port to the suction side of said compartment.

9. An air conditioner in accordance with claim 6 in which said port from the passageway to the compartment having the heat dissipating element constitutes an outside air inlet and the passageway constitutes a bypass around said port to the air inlet to the other compartment when said port is closed by said damper.

l0. An air conditioner in accordance with claim 6 in which the passageway constitutes a bypass around the air inlet to the compartment having the hea-t absorbing element when said damper is adjusted to open the port from the passageway to the compartment having the heat dissipating element and close the passageway between said port and the outside ambient.

1l. In a room air conditioner of the type having a compartmentV with a heat absorbing element therein through which a stream of room air is circulated in a predetermined path and an adjacent compartment with a heat dissipating element therein through which a stream of outside air is circulated in a predetermined path, the combination with such a room air conditioner of a port opening between the compartments, a single damper for closing the port opening in one position and movable to a plurality of other positions, and said port opening and damper being so constructed and arranged with respect to the paths of the air streams in the different compartments as to induce the flow of outside `air through the port opening into the room in one of said plurality of positions and induce the ow of room air through the port opening to the outside in another of said plurality of positions.

12. An air conditioner having a housing divided into adjacent compartments, a refrigeration system having a heat absorbing element in one compartment and a heat dissipating element in the adjacent compartment, each of said compartments having an air inlet and outlet, means for circulating room air and outside air through the respective compartments, a passageway between compartments, a damper having at least one vane for closing the passageway and movable to a plurality of other positions, said damper in one of said plurality of other positions opening a path from the air inlet to one compartment to the passageway and bathing the llow of air from the passageway to the outlet from said compartment, and

said damper in another of said plurality of other positions closing the path from the air inlet to the passageway and opening a second path from said passageway to the air outlet from said compartment.

5 References Cited in the le of this patent UNITED STATES PATENTS 877,648 Keith Jan. 28, 1908 1,072,189 Sparks Sept. 2, 1913 10 1,487,828 Ziganek et al. Mar. 25, 1924 1,684,601 Shpater Sept. 18, 1928 10 Meyer Aug. 16, Burman Ian. 3, Moore Mar. 11, Berg Sept. 29, Smith Sept. 5, Eberhart Oct. 8, Hart Oct. 25, Morgan Oct. 17, Tipton Dec. 1,

FOREIGN PATENTS Australia Apr. 4, 

